Faculty of Health Sciences & Medicine

Future Research Projects

DNA Markers for Human Physical Appearance

Supervisor

Prof Angela Van Daal
Professor of Forensic Sciences

BACKGROUND

The ability to determine the physical characteristics of an individual depositing a biological stain at a crime scene would provide important probative information to law enforcement investigators.  The success of such studies would herald an exciting new post-genomic era in forensic biology in which novel phenotypic information about the donor of the body fluid could be obtained directly from the physiological stain itself. This ‘genetic eyewitness’ evidence should assist law enforcement in developing or excluding suspects in criminal cases and could help clarify conventional eye witness accounts. The physical appearance of an individual is encoded in his/her genome as evidenced by the striking physical similarity of identical twins. While some characteristics are significantly affected by the environment, others are largely determined as a result of genetic make-up and are highly heritable. These include the major physical descriptors of a person, namely their height, colouring and facial features. A number of DNA differences or single nucleotide polymorphisms (SNPs) have been associated with various hair, skin and eye colour phenotypes and more recently with height variation.

AIMS OF THE PROJECT

The aim of this proposal is to develop a set of forensic biomarkers for assessment of physical characteristics of DNA depositors or skeletal remains. The proposed work seeks to assemble a panel of SNPs associated with human pigmentation and height variation. These polymorphisms would be molecular predictors of height for use in assays on crime scene samples. This project aims to develop a SNP panel containing SNPs that can be used to predict the hair, skin or eye coloring phenotypes of the sample source. It also aims to develop a SNP panel containing SNPs that can be used to predict the height of the sample source.

METHODS

The project will use a sample collection of greater than 700 individuals with phenotypic data relating to height, weight, pigmentation, ancestry and facial morphology recorded. The strategy will be to identify and combine SNPs that have been shown to be causal or strongly associated with the determination of normal human hair, skin or eye colour variation or normal height variation. These SNPs will be assessed for their cumulative predictive power in different population groups and combined into a multiplex assay using Oligonucleotide Ligation Assay/PCR technology for allelic discrimination. The panel will be validated on population samples representative of the major population groups. This can then be followed by analysis of these SNPs in a population with a characterised range of pigmentation or height phenotypes.